Method of processing overcoated lithographic printing plate

Inactive Publication Date: 2009-10-01
TENG GARY GANGHUI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0016]The overcoat is soluble or dispersible in water or an aqueous solution, and is capable of removal from the plate by brushing or rubbing while in contact with water or an aqueous solution. However, preferably, the overcoat has good moisture resistance and does not come off the plate quickly when contacted with water or an aqueous solution without brushing or rubbing. More preferably, the overcoat is sufficiently moisture-resistant and non-tacky so that the plate does not form fingerprints when handled by hands. Most preferably, the overcoat is sufficiently block-resistant so that it can be stacked over one another non-interleafed during storage without blocking to one another, and the plate is supplied as stack of plates without interleafing paper in between.

Problems solved by technology

Preferably, the overcoat is incapable of being completely removed on press with ink and / or fountain solution during the roll up.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

examples 1-8

[0105]An electrochemically grained, anodized and polyvinyl phosphonic acid treated aluminum substrate was first coated with a 0.1% aqueous solution of polyvinyl alcohol (Airvol 540, from Air Products) with a #6 Meyer rod, followed by drying in an oven at 100° C. for 2 min. The polyvinyl alcohol coated substrate was further coated with a thermosensitive layer formulation PS-1 with a #6 Meyer rod, followed by drying in an oven at 100° C. for 2 min.

PS-1ComponentWeight (g)Neocryl B-728 (Polymer from Zeneca)2.50Ebecryl 220 (Acrylate monomer from UCB Chemicals)5.99Pluronic L43 (Nonionic surfactant from BASF)0.40(4-(2-Hydroxytetradecyl-oxy)phenyl)phenyliodonium1.00hexafluorophosphatePINA KF-1151 (Infrared absorbing polymethine dye from0.10Allied Signal)2-Butanone90.00

[0106]The thermosensitive layer coated plate was further coated with a water-soluble overcoat OC-1 using a #12 Meyer rod, followed by hot air blow drying and baking in an oven at 100° C. for 2 min.

OC-1ComponentWeight ratiosAir...

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PUM

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Abstract

A method of processing an on-press developable lithographic printing plate involves the removal of overcoat by brushing or rubbing while in contact with water or an aqueous solution after imagewise exposure and before on-press development. The plate comprises a substrate, an on-press ink and / or fountain solution developable photosensitive layer, and a water soluble or dispersible overcoat. Preferably, the overcoat is incapable of being completely removed with ink and / or fountain solution on a lithographic press during roll up. Such a method allows the use of more durable overcoat for on-press developable plate.

Description

FIELD OF THE INVENTION[0001]This invention relates to lithographic printing plate. More particularly, it relates to a method of on-press developing a lithographic plate involving the removal of overcoat before mounting on press.BACKGROUND OF THE INVENTION[0002]Lithographic printing plates (after process) generally consist of ink-receptive areas (image areas) and ink-repelling areas (non-image areas). During printing operation, an ink is preferentially received in the image areas, not in the non-image areas, and then transferred to the surface of a material upon which the image is to be produced. Commonly the ink is transferred to an intermediate material called printing blanket, which in turn transfers the ink to the surface of the material upon which the image is to be produced.[0003]At the present time, lithographic printing plates (processed) are generally prepared from lithographic printing plate precursors (also commonly called lithographic printing plates) comprising a substra...

Claims

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Application Information

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IPC IPC(8): G03F7/12
CPCB41C1/1008B41C1/1016B41C2201/02B41C2201/10B41C2201/14B41C2210/24B41C2210/08G03F7/11G03F7/26G03F7/38B41C2210/22B41C2210/04
InventorTENG, GARY GANGHUI
OwnerTENG GARY GANGHUI